Mixer and distributor for pneumatic transported pulverized material



MIXER AND DISTRIBUTOR FOR PNEUMATIC TRANSPORTED PULVERIZED MATERIAL Oct.6, 1931. J. E. KENNEDY Filed March 16, 1928 2 Sheets-Sheet \NVENTOR J5Kennea 2 OR BY Oct. 6, 1931. J, E, KENNEDY 7 1,825,668

MIXER AND DISTI RIBUTOR FOR PNEUMATIC TRANSPORTED PULVERIZED MATERIALFiled March 16, 1928' 2 Sheets-Sheet 2 fly llllllll INVENTOR L J 5/@2777Zf Mom: Y

Patented Oct. 6, 1931 I UNITED STATES PATENT OFFICE JOSEPH E. KENNEDY,OF NEWYORK. N, Y.

MIXER AND DISTRIBUTO R FOR PNEUMATIC TRANSPORTED PULVERIZED MATERIALApplication filed March 16, 1928. Serial No. 262,097.

This invention relates to means for use in the pneumatic transportingand distribution of pulverized material in a system for the delivery ofa fuel mixture, such as pulverized coal in suspension in anair streamfrom a source of supply, which may be a disintegrating apparatus or astorage bin, to a'place of combustiomsuch as a burner or burners leadingto a furnace orboiler,and it is the object of the invention to providemeans to be interposed in a pneumatic pulverized coal delivering systemfor eiiecting a mixing and establishing of an equal distribution ordensity of the coal particles throughout the air stream in such a mannerthat when the main stream is distributed or divided into divisionalstreams the pulverized material or coal in each divisional stream willbe of the same density; that is, the streams will each carry the sameamount of solid material in proportion to the amount of air, and toprovide means for this purpose which is simple in construction andefiicient in operation.

The presentinvention is an improvement upon the mixing and distributingmeans dis' closed in my co-pending application Serial N 0. 211,696,audit is the principal object of the invention of the presentapplication to provide means to effect a more thorough distribution andequal density of thecoal particles throughout the air stream by which itis transported, tofacilitatethe dividing of a main stream in divisionalstreams, and to assure the maintaining of the equal density of the coalparticles throughout the cross section of each of the divisionalstreams.

In the drawings accompanying and forming'part of this application Figure1 is a longitudinal sectional view of mixing and distributing meansillustrating an emb0diment of the invention. 7 i

Figure 2 is a plan view, partly broken away, looking atthe top of Figure1.

Figure 3 is a side elevation of an agitator constituting a part of themixing and distributing means.

Figure 4 is a cross sectional view taken on the line 4.4'of Figure 3looking in the direction of the arrows. Y

V Figure 5 is'a longitudinal sectional view showing a modification ofthe inlet means to the mixing and distributing means and a modifiedarrangement of the agitator.

Figure 6 is a cross sectional view taken on the lines- 6- 6 ofFigure 5.looking in the di rection of the arrows togshow the arrangement ofmixing and agitating blades on a carrier head therefor; and

Figure 7 is a sectional view, partly broken away, taken on the line71-77 of Figure 5 looking in the direction of the arrows to show thearrangement of the outlet means from the mixing and distributingameansinrelation to the mixing and agitating means.

In carrying out the embodiment of the invention shown in Figures 1 to lthere is provided a casing 8, preferably of truncated conical form,arranged'with closure plates 9, 10 at opposite ends. The casing isarranged with inlet means comprising a pipe or conduit coupling member11 connected to the end of the casing of smaller diameter and leadingthrough an opening-in the casing substantially tangential to the sidewall thereof, as

shown in Figure 2. The outlet means comprises openings 12 through theperipheral portion of the plate 10 at the larger end of the casing, saidopenings being of elongated segmental shape and of restricted width andequidistantly spaced about the plate, the openings being in number equalto the number of divisional streams into which the mainstreamenteringthe casing throughthe inlet meansll is to be divided. Inthe present instance two of such openings are provided arrangeddiametrically opposite with pipeor conduit coupling members 13 connectedthereto,-said coupling members having the end at which they areconnected with the outlet openings arranged of arcuate form, as at 14,to correspond with the openings 12 and of circular form at the outerend. The inlet means 11 is connected through a main conduit with a fanoutlet the inlet of which is connected with the source of supply, whichmay be a pulverizing apparatus or a storage bin, the pulverized materialbeing drawn with air from the source of supply and transported by suchair stream or column with the pulverized material in suspension therelnthrough the inlet means 11 to the casing. The pulverized material ladenair is delivered from the casing through conduits or pipes connectedwith the outlet coupling members 13 to burners connected with saidoutlet conduits and arranged in relation to a furnace or furnaces.

In delivery systems for pulverulent material of this character whereinthe material is transported in suspension in an air stream through aconduit leading from a fan by which it is drawn from the source ofsupply, there is a tendency of the pulverulent material to assume anunequal density throughout the width of the stream or column with theresult that the stream is composed of strata having different density ofpulverulent material. This is especially so when additional air issupplied to the column of air with the pulverulent material insuspension delivered by the fan. It has been found that this inequalityin density is maintained when the main stream or column is distributedto the branch conduits with the result that one or mpre of the branchstreams may transport such a small amount of the pulverulent material orsolids that combustion thereof will not take place at the burner orburners connected with said conduits.

To overcome this disadvantage and maintain the density of the divisionalstreams means are arranged in the casing to agitate the pulverizedmaterial laden air to mix the coal particles therewith and therebyeffect or establish an equal distribution or density of the pulverizedmaterial throughout the air and in said condition deliver the pulverizedcoal carrying air in divisionalstreams to the branch conduits andthereby to the burneis connected therewith. This agitator meanscomprises a head 15 of truncated conical form nd of les cross sectionalarea than the cars ing with the base of the head of a diameter to comewithin the openings 12 in the closure plate 10 for the base of the casing, whereby a space is provided between the head and the casing wall.The allof the headis arranged at a more acute angle to the base than theside wall of the casing whereby the space between the head and easing atthe smaller end is of greater width than at the base end to proportionthe head relative to the casing so that the space between the head andeasing wall in all cross sectional portions thereof will be of equalarea or volume, and preferably being of the same cross sectional area asthe main conduit connected with the casing through the coupling member11 and also of the branch conduits connected with the coupling members13. Vancs or blades are secured to the head, as by welding, and extendlongitudinally of the head in spiral formation, certain of the bladesequidistantly spaced about the head, as the blades 16, extending for thefull length of the head. while intermediate blades extend from the baseof the head for only a portion of-the length thereof, equidistantlyspaced blades 17 of said blades extending for substantially two-thirdsof the length of the head, while further equidistantly spaced blades 18and interposed between the blades 16, 17, extend for only substantiallyone-third the length of the head. A shell 19 is extended about the headblades and by means of which blades the shell is united with the head torotate therewith, as by welding the shell to the blades. The shell 19extends from the opening of the inlet means 11 to adjacent the base ofthe agitator head and in spaced relation to the casing plate 10, wherebythe space between the head and shell at one end is in communication withthe space in the easing into which the inlet means opens and terminatesadjacent the outlet means 13.

The head 15 is fixed to a shaft 20 the ends of which shaft are extendedthrough axial opcnings in the casing plates 9. 10 and journaled byanti-friction hearin gs 21 in bearing blocks 22 fixed to the outer sideof the plates 9. 10 and held against axial movement by perforated caps23 secured to the bearing blocks cooperating with the bearings 21.

In the operation of the apparatus as described the pulverized materialladen air stream entering the casing 8 through the inlet means 11striking against the blades 16 imloo parts rotatiy e movement to theblade ca rryingnhead or agitator, the revolving of the agitator settingup aswirling of the air stream entering the chamber and thereby thethorough mixing of the pulverized material with the air so that the samewill be of equal density throughout the air in the chamber. By thearranging of the agitator head at a more acute angle than the wall ofthe casing and thereby in effect converging the wall of one relative tothe other, there is induced a movement or flow of the agitated air inthe casing in a direction longitudinally of the agitator head toward theoutlet openings 12 distrihut ing the air with the pulverized material ofequal density therein through said openings to the coupling members 13and conduits connected therewith and to burners connected with saidbranch conduits.

In the modified arrangement shown in Figures 5 to 7, inclusiverthecasing and agitator are inverted, the plate 10 with the outlet Openings12 and coupling members 13 being at the top. Instead of the inlet meansto the casing being through the side wall tangential to'the agitatorhead said inlet means is axial to the smaller end of the casing and ofthe agitator. For this purpose the closure plate 9 utilized in theFigure 1 structure is eliminated and a coupling member, or the conduitfor the main stream and leading from the fan outlet, is connecteddirectly to the smaller end of the casing, as at 25 in Figure 5. Thewall of the agitator head is also arranged at a more acute angle thanthe inclination of the casing wall similar to the Figure 1 structure,and the head is carried by the shaft 20 rotatable axially of the casing,the one end of said shaft being journa-led in a hearing, as at 26, in aspider 27 secured in the smaller end of the casing. The shell 19 is alsoprovided, the same being inclined at the same angle and lies contiguousto the casing wall. This shell, however, extends from the opening to thecasing whereby the incoming stream is directed to the blades betweensaid shell and agitator head and extends for the greater part of, thelength of said head. Van-cs or blades, as shown at 16, to eiiect aswirling of the air stream entering the casing and a consequent mixingand equal distribution of the coal particles through the air, extendfrom point within the base of the agitator head and the one end of theshell adjacent to the apex of the head and terminate within the end ofthe shell at the entrance to the casing, said blades serving to unitethe shell with the head to rotate therewith by welding the blades orvanes at the longitudinal edge portions to the head and shell. Theblades are arranged in spiral form longitudinally of the agitator head,as shown in Figure 6. While the force of the air stream entering thecasing and leading to the space between the shell and agitator headstriking against the vanes will impart rotary movement to the agitator,in this arrangement the agitator is preferably positively driven. Theagitator may be driven from a suitable source of power, but preferablycomprises an electric motor, shown in a conventional manner at M,mounted upon blocks 28 upon the casing and cperatively connected withthe agitator carrying shaft 2 by a coupling 29. It will be obvious thatthe agitator in the Figure l arrangement may also be positively drivenby connecting a pulley to either of the extended ends of the agitatorcarrying shaft 20, or by a motor mounted upon the casing 8 and coupledwith the agitator carrying shaft.

Having thus described my invention 1 claim:

1. In a mixer and distributor for pulverized material transported insuspension in an air stream, a casing having inlet and outlet meansarranged for connection in a conduit, ahead of less cross sectional areathan and rotatable in the casing, a shell extended about and spaced fromthe head in the easing with the space between said head and shell incommunication with the inlet and outlet means of the casing for thepassage of the pi'ilverulcnt material laden air stream therethrough, andmeans to unite said shell with the head to rotate therewith and arrangedto a itate the pulverulent material. laden air in its passage throughthe casing.

2. In. means for mixing and distributing pulverized material tra sportedin suspension in an air stream, a casing having an inlet at one endarranged for connection of an air stream transporting conduit andoutlets at the opposite end arranged for connection of branch conduits,and means rotatable in the casing operative to agitate and induce a flowof the stream through the casing from the inlet to the outlets, saidinlet and agitator means being constructed and arranged whereby thestream entering the casing will set rotation of the agitator.

ell

3. In a mixer and distributor for pulverized material transported insuspension in an air stream. a casinghaving inlet and outlet meansarranged for connecting the casing with stream transporting conduits, anagitator comprising a head rot'atab e axially in the casing and havingvanes circumte'rem tially disposed about the same, and a shellencircling and rotatable with the head'and spaced therefrom by thevanes, with the inlet and outlet means leading to and fromthc spacebetween the head and shell.

at. A mixer and distributor for airtransported pulverized material asclaimed in claim 3, wherein the casing and head are of truncated conicalform with the head of less 1 cross sectional area than the casing andhav- 111g inlet means at the smaller end of the casing and outlet meansat the larger end.

7 5. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the casing and head are of truncated conicalform with the head of less cross sectional area than the casing and thewall of the head inclined at a more acute angle than the wall of thecasing.

6. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the casing and head are of truncated conicalform with the inlet means leading to the smaller end of the casingtangential to the head and the outlet means leading from segmentalopenings in and circumferentially disposed about a closure plate, forthe larger end of the casing.

7. mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the vanes are arranged spirallylongitudinally of the head and the shell is of less length than the headand arranged to extend at the same inclination as the wall of the casingand to lie contiguous thereto.

8. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the inlet means is to the smaller end of thecasing tangentially to the head, and the shell is arranged at the sameinclination as the casing wall and lies contiguous thereto, and saidshell is of less length than the head and terminates at the side of theinlet means.

9. A mixer and distributor for air transported pulverized material asclaimed in claim 3 wherein the agitator and inlet means are arrangedwhereby the stream entering the casing is directed against the vanes ofthe agitator to impart rotatiy e movement thereto.

10. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein certain vanes extend the full length of thehead and other vanes extend for only a portion of the length of thehead.

11. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the shell extends from the base for only aportion of the length of the head. and certain vanes extend for the fulllength of the head and other vanes extend for only a portion of thelength of the head.

12. In a mixer and distributor for air transported pulverized materialas claimed in claim 3, a motor mounted on the casing and having anoperative connection with the head to rotate the same.

13. A mixer and distributor for air transported pulverized material asclaimed in claim 3. wherein the head is lixed to a shaft rotatablymounted and supported by the easing with a portion of the shaft extendedto the exterior of the casing arranged for the connection of means torotate the head.

14. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the inlet means leads to the smaller end ofthe casing, and the outlet means leads through segmental openings in theperipheral portion of a closure plate at the base end of the casing.

15. A mixer and distributor for air transported pulverized material. asclaimed in claim 3, wherein the inlet means leads to the smaller end ofthe casing, and the outlet means leads through segmental openings in aclosure plate at the opposite end of the casing, and the base of thehead being of a diameter to come within said closure plate openings andarrange the space as a passage through the casing to the outlet means.

16. A mixer and distributor for air transported pulverized material asclaimed in claim 3, wherein the inlet to the casing is at the smallerend concentric with the axis of the casing and the outlet is throughsegmental openings in a closure plate at the base of the casing, thebase of the agitator head being of a diameter to come within theopenings in said closure plate and the side wall inclined at a moreacute angle than the wall of the casing, and the shell being inclined atthe same angle and arranged contiguous to the casing wall and extendingfrom the inlet end of the casing to a point within the base of theagitator head.

Signed at the city of New York, in the county of New York and State ofNew York, this 10th day of March, 1928.

JOSEPH E. KENNEDY.

